Wooden Boat People
By McKenzieDriftBoat.com
Meranti vs okoume?
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Replies to This Discussion
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Permalink Reply by Randy Dersham on
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You need to be careful when you use the term Meranti. There is a lot of crap Meranti plywood on the market. The best is called Hydrotek. You want to use a 5 ply BS1088 marine Meranti only.
Joubert Okoume is also BS1088 and is Lloyds Registered. It is more expensive because of the register. It is a very fine high quality marine plywood that is used often for boat building where weight is the primary concern. You will see it used on almost all kayak kits. They require light weight and almost always use glass on the outside of the boat.
Plywood framed driftboats can be made with 1/4 (6mil) plywood. Meranti does not require the glass. Okoume should have glass in my opinion. It is softer than Meranti. Most stitch and glue driftboat builders user 3/8 in (9mil ) plywood and glass.
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Permalink Reply by j szerlag on
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Thanks Randy. Is it over kill to glass the meranti BS1088? Im looking for strength.
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Permalink Reply by lhedrick on
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In the case of glassing plywood, the plywood is most of the structural part. The glass adds stiffness and seals the wood off from water.
I think Okoume is about 40 percent more these days. It works differently the hydrotek and aquatek brands which it think is due to the difference in glue. The last time I tried to hand plane hydrotek it gummed up the plane. Never had that trouble with okume. Can't say one is better then the other.
The framed boat builders here are the authority on the process of famed construction. I build using the stitch and glue method. With S&G the major joints are bonded together with many layers of glass and epoxy. The framed boats use screws and joint compound with the screws locking plywood joints to frames and chine caps.
Strength is kind of a wild card term in all of this. It's not easy to explain the structural properties of drift boats in terms of plywood and fiber glass. There are clearly overlapping properties. There a builders who assemble white water boats of foam core which has no strength at all. White water framed boats of the past used no glass and were plenty strong.
I have been leaving wood construction just because I am seeing the quility of the plywood going down hill. Unless you purchase graded wood, the stuff is going down hill fast. So, I am moving to composites which are also lighter. More discussion then that is for another place as this is a wood builders forum.
A well cared for all Okoume boat will look like a million bucks but, it will need some TLC to keep it looking beautiful. My composite boats get painted. They are tough and light but will never have the charm of an all wood boat.
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"Is it overkill to glass the meranti BS1088. I'm looking for strength."
Before answering your question you need to decide if you are going to build with frames or stitch and glue. With frames epoxy and glass would be optional. With stitch and glue, it certainly would be advisable. In either case, the epoxy/glass will produce a craft that requires less maintenance, especially if painted.
In stitch and glue all of the wood needs to be encapsulated in epoxy. Glass and epoxy will be required to secure the various panel joints. Glass gives both the epoxy and plywood panel additional abrasion resistance and puncture resistance.
Montana Boatbuilders has a website with pics and examples of stitch and glue okoume boats. I believe they use 6 oz glass on the exterior of the side panels, but only coat the interior with epoxy. They build with 9 mm plywood.
Montana Riverboats has plans that call for using 6 mm plywood side panels (1/4 inch), and the plan instructions glass both the interior and exterior of the side panels. The bottom panel is glassed on both sides.
A number of the frame builders and kits from Oregon use glass/epoxy on the inside of the bottom panel to resist fracturing the bottom when hitting rocks (it does happen...both the hits and fractures).
As Larry states, most of the strength comes from the plywood panel. Reinforcing those panels will improve their performance up to a point. Then you are adding more weight than you are gaining in performance.
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Thank you eric this is all new to me. I am doing a ton of research. Every bit of information helps. I think after all of my research I am going to purchase plans from altair industries the 16' McKenzie river driftboat. Does anyone have any experience with these plans and if so any tips? I want to thank everyone for all of their help. J
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Permalink Reply by Rick Newman on
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Before I spent the money on the plans I would read Roger Fletcher's "Drift Boats and River Dories" available at Riverstouch.com. If nothing else it will give you a better foundation for your boat building than simply a set of plans. To me nothing beats knowing why something is built the way it is. The education that this book provides is invaluable or in common vernacular "priceless".
Rick Newman
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Permalink Reply by Seamus Walsh on
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buy Fletcher's book and save the cash for a kevlar bottom, nicer hardware, or something more useful than plans.
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Permalink Reply by Dave Z on
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You should decide what you are going to use the boat for, and second guess your selection based on "strength." The waters you intend to visit should factor into your selection. Personally, if a guy could get quality AA fir, thats all I'd use. Those days are long gone. But Meranti is pretty darn nice to work with and the BS1088 Hydrotek that Randy recommends is the ONLY "Meranti" to use. Its very clean, consistent and if you pick through a pile and get consecutive sheets, you can get the colors matched up pretty well. I beleive it is the same weight per sheet as 1/4" fir.
A framed boat is a pretty "strong" structure. I think once you tie it all in, chines, frame members to top rails, its pretty strong regardless of the wood used for the hull sides. Some wood smay impact fracture or puncture easier than others, but regardless of the material, you gotta develop the skills to stay away from those hits!
Oh yeah, and I'll repeat the broken record of advice- buy Roger's book. The plans in it are historic collections, and the insight you'll gain from reading it will supplement the advice form this forum. Good luck. Buy it directly from the man himself, he'll autograph it for ya. haha
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I bought the book. It wil be here in a few days. Thanks again for all the help. J
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